Source: Shanghai hydrowei machinery hydrowei 2022-04-01 00:00
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#1 lawrencelivermore Laboratory
#Metal hydrogen storage 1
#Magnesium diboride hydrogen storage 1
#Magnesium hydrogen storage 1
#1 alloy hydrogen storage
Hydrogen absorption on the surface of magnesium diboride was studied by first principles simulation.
Scientists at lawrencelivermore National Laboratory (LLNL) simulated the hydrogen storage reaction of a promising material and found out why the hydrogen absorption rate of the material became slower, thus providing insights that can be used for improvement.
Improving hydrogen storage in solid materials depends on a better understanding of the multistep chemical reactions that occur at complex interfaces. At these interfaces, the material changes from non hydrogen containing to hydrogen containing saturated phase, because its constituent molecular units react and combine with hydrogen and rearrange structurally. From hydrogen storage materials to batteries, similar transformations control various chemical and electrochemical energy storage environments.
To reveal the potential mechanism of magnesium diboride (MgB2) hydrogenation, a team of LLNL scientists used molecular dynamics simulations. They found that magnesium ion (mg2+) drives the polarization and charge redistribution of molecular units, which is the key to the cracking of boron (b) from the raw MgB2 material, and makes boron (b) atoms combine with hydrogen sequentially to form a hydrogen saturated Mg (BH4) 2 phase. Specifically, the nearby mg2+ ions polarize the BHX unit, attracting the positively charged boron atom in the center and combining with the negatively charged hydrogen ion, which is negatively charged through the interaction with mg2+. The study was published in the journal Applied Materials and interfaces.
The analysis also revealed the possible reason why the hydrogen absorption rate of MgB2 slowed down during the formation of Mg (BH4) 2, thus preventing the complete hydrogenation without high temperature and high pressure in the experiment. The boron contained in MgB2 hexagonal sheet is not very stable, so when the magnesium content in local environment is low, boron is easier to combine with hydrogen. However, with the conversion of the material to Mg (BH4) 2, the surface magnesium content of the remaining MgB2 material increases and the hydrogenation rate slows down.
"Our simulation captures the reaction path leading to hydrogen absorption in MgB2," said Keith ray, a physicist and author of LLNL. "It is hoped that this understanding will contribute to further research on rapid hydrogenation at lower temperature and pressure."
Other authors of LLNL include shinyoung Kang, Liwen Wan, Sichi Li, Tae wook hee, Jonathan Lee, Alexander Baker, and Brandon wood. This work was funded by the Ministry of energy, the office of energy efficiency and renewable energy, and the office of hydrogen and fuel cell technology, including the hydrogen materials advanced research alliance.
The laboratory was co founded by Ernest O. Lawrence and Edward teller. It began operation on September 2nd, 1952. Herbert York served as the first director.
"New
ideas" lab was born in the Cold War
Lawrencelivermore
National Laboratory (LLNL) was established in 1952 at the height of the cold
war to meet urgent national security needs by promoting nuclear weapons science
and technology.
In its history,
through its talented and dedicated staff and world-class research capabilities,
the laboratory has strengthened national security with the tradition of
scientific and technological innovation - predicting, developing and providing
solutions to the country's most challenging problems.
For 65 years, LLNL
has been making history and making difference.
Hydrogen storage reactions bear a complex dance toward faster uptake |
Lawrence Livermore National Laboratory (llnl.gov)
March 30,
2022
